IRFZ44 MOSFET — Specifications & Equivalents
Manufacturer: Commonly produced by International Rectifier (now Infineon)
About the IRFZ44
The IRFZ44 is an N-channel MOSFET with a drain–source voltage (VDS) rating of 60 V, a continuous drain current (ID) of 50 A and an on-resistance (RDS(on)) of 0.028 Ω. It can dissipate up to 150 W and is rated to a junction temperature of 175 °C. It is supplied in the TO220 package.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 60 V
- Max continuous drain current (ID): 50 A
- On-resistance (RDS(on)): 0.028 Ω
- Gate threshold (VGS(th)): 4 V
- Power dissipation (PD): 150 W
- Max junction temperature (TJ): 175 °C
- Package: TO220
- Manufacturer: Commonly produced by International Rectifier (now Infineon)
Typical applications
With its 60 V drain–source rating the IRFZ44 sits in the mid-range class of switching MOSFETs, typically found in 24 V and 48 V industrial and battery systems, motor drives and H-bridges and load and hot-swap switching.
The 50 A current rating puts it in high-current territory, where conduction loss (I² × RDS(on)) and thermal design usually matter more than switching loss. Budget for adequate copper area and a heatsink.
The low 0.028 Ω on-resistance keeps conduction loss down, which suits synchronous rectification and continuous high-current paths.
Gate drive and switching notes
With a gate threshold (VGS(th)) of 4 V this is not a logic-level device: driving the gate directly from a 3.3 V or 5 V microcontroller pin will leave it only partly on and cause it to overheat. Use a gate driver or level shifter, typically taking VGS to 10 V.
Keep gate–source voltage within the ±20 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.
Total gate charge (Qg) of 67 nC sets the drive current required: average gate current is roughly Qg × switching frequency, so faster switching needs a stronger driver.
Switching behaviour is characterised by a rise time of 110 ns and an output capacitance (Coss) of 920 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the IRFZ44
A drop-in substitute for the IRFZ44 must be the same N-channel type and offer a drain–source rating of at least 60 V, a continuous drain current rating of at least 50 A, an on-resistance no higher than 0.028 Ω if efficiency and heat matter and a comparable gate threshold, so your existing gate drive still fully enhances the device.
Mechanically, check the replacement against the TO220 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.
Where the application switches inductive loads or runs near the voltage limit, keep extra headroom rather than choosing a part that only just meets the original numbers.
Frequently asked questions
What is the IRFZ44?
The IRFZ44 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 60 V drain-source and 50 A continuous drain current.
What is the maximum voltage of the IRFZ44?
The IRFZ44 has a maximum drain-source voltage (Vds) of 60 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the IRFZ44 handle?
It is rated for 50 A of continuous drain current, with power dissipation limited to 150 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the IRFZ44?
On-resistance (Rds(on)) is 0.028 Ω. Multiply by the square of your load current to estimate conduction loss.
Is the IRFZ44 logic-level compatible?
No. The gate threshold is 4 V, so a 3.3 V or 5 V logic output cannot fully turn it on. Use a gate driver and take Vgs to around 10 V.
What package does the IRFZ44 come in?
It is listed in TO220. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the IRFZ44?
No verified equivalents are listed yet. Choose a part of the same polarity that meets or exceeds every rating above and shares a compatible package and pinout.
Key Specifications
| Type | MOSFET |
|---|---|
| Channel Type | N -Channel |
| Drain-Source Voltage (Vds) | 60 V |
| Gate-Source Voltage (Vgs) | 20 V |
| Gate Threshold Voltage (Vgsth) | 4 V |
| Drain Current (Id) | 50 A |
| Drain-Source On-Resistance (Rds) | 0.028 |
| Total Gate Charge (Qg) | 67 |
| Rise Time (tr) | 110 nS |
| Output Capacitance (Coss) | 920 pF |
| Junction Temperature (Tj) | 175 °C |
| Package | TO220 |
| Power Dissipation (Pd) | 150 W |
Equivalent & Replacement Parts
No verified equivalents are listed for IRFZ44 yet.